Re: [WISPA] Transmit Antenna Height
At 10/1/2010 12:33 AM, you wrote: Fred, I think were saying the same thing? I wrote mine before receiving yours, but in any case, we were giving different information relevant to the topic. You gave a good link for a site to compute the HAAT of a given location. I went a bit deeper into the FCC's own wording and Comment reference to show what they apparently meant to do with the rule. -- Fred Goldsteink1io fgoldstein at ionary.com ionary Consulting http://www.ionary.com/ +1 617 795 2701 WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] Transmit Antenna Height
What are the headings for your chart? I don't
understand it
On 09/30/2010 08:13 PM, Fred Goldstein wrote:
At 9/30/2010 10:37 PM, Jack Unger wrote:
Fred,
I'm sorry to seem dense but I don't understand your explanation below.
I'd appreciate it if you would re-explain. The FCC said:
"transmit antenna used with fixed devices may not be more than 30
meters above the ground. In addition, fixed devices may not be located
at
sites where the height above average terrain (HAAT) at ground level is
more than 76 meters".
I'm trying to reconcile that with your statements. Could you please
re-explain more clearly or by using better actual numbers (both HAAT at
ground level and antenna height above ground)?
Thanks in advance,
jack
Sure. In the Order itself, the FCC explained the origin of the 76
meter HAAT limit. They explained that they didn't want any antennas
more than 106 meters AAT. That's the maximum antenna HAAT I
referred to. Since antennas are allowed to be 30 meters above
ground, they subtracted 30 from 106 and got 75. See paragraph 66 of the
Order:
"We find that
limiting the fixed device antenna HAAT to 106 meters (350 feet), as
calculated by the TV bands database, provides an appropriate balance of
these concerns. We will therefore restrict fixed TV bands devices from
operating at locations where the HAAT of the ground is greater than 76
meters; this will allow use of an antenna at a height of up to 30
meters
above ground level to provide an antenna HAAT of 106 meters.
Accordingly,
we are specifying that a fixed TV bands device antenna may not be
located
at a site where the ground HAAT is greater than 75 meters (246
feet)."
The Order cited an IEEE 802 Petitition
http://fjallfoss.fcc.gov/ecfs/document/view?id=6520201311
which
called for HAAT to be a factor. But they didn't call for a ban on
operation above 75 meters; rather, they wanted co-channel separation to
increase with height:
less than 3
meters
| 6 km
0.1 km
3 Less than 10 meters*
6.9 km
0.256 km
10 Less than 30 meters
10.8 km
0.285 km
30 Less than 50 meters
13.6 km
0.309 km
50 Less than 75 meters
16.1 km
0.330 km
75 Less than 150 meters
22.6 km
0.372 km
150 Less than 300 meters
32 km
0.405 km
300 Less than 600 meters
45.7 km
0.419 km
600 meters or higher
68 km
0.426 km
That's rational. On the other hand I'd prefer allowing fixed
devices at any ground elevation, to allow everyone to subscribe, so I'd
suggest instead that they maximum ERP be decreased in order to limit
interference to the same level. So maybe 6 dB from 76 to 150 meters
and 10 dB to 300 meters, though that's a guess; I haven't run the
calculations. And I'd allow directional antennas, professionally
installed, to have ERP measured in the direction of the protected
contour, with no reduction in ERP if it's clear to the distance the
above
chart.
I'm thinking about a petition to that effect. I have real
subscriber sites in mind.
On 9/23/2010 4:48 PM,
Fred
Goldstein wrote:
The rules allow antenna heights up to 30 meters, around 100 feet.
One problem with the maximum HAAT limit is that it applies to the
ground
height, based on having a 30 meter high antenna. In other words,
the ruling assumed a maximum antenna HAAT, and then set the ground HAAT
to be 30m below that. If somebody's house is 10m below the
limit, then a 10m antenna should be legal. (The minimum antenna height
went away, since sensing is no longer required. That frankly seems
to be the only major improvement in the rules.)
Brian
From:
wireless-boun...@wispa.org
[
mailto:wireless-boun...@wispa.org]
On Behalf Of Tom
DeReggi
Sent: Thursday, September 23, 2010 7:32 PM
To: WISPA General List
Subject: Re: [WISPA] Transmit Antenna Height
Yeah, that really sucks. Many areas needing served have thick
forest/trees easilly 70ft tall.
A 90ft height, just wouldn't allow enough of the signal to have open
air,
and the signal would be going through trees most of the full path.
In 900Mhz, the difference between having the tower side over the tree
line and below the tree line can be the difference between a quarter
mile
coverage and a 7 mile coverage in our market.
All be it, 700Mhz does have better NLOS propogation characteristics
than
900 does.
I would have liked to see that height doubled.
However, admittedly, it will allow much better spectrum re-use in areas
that h
Re: [WISPA] Transmit Antenna Height
At 10/1/2010 02:27 PM, Matt Jenkins wrote: What are the headings for your chart? I don't understand it Eudora had trouble with cut-and-paste of the original document. The first column is height above average terrain, from x to y meters (10 but less than 30, from 30 but less than 50...). The second is the proposed distance outside of the protected contour of a co-channel station. THe second (the small distance) is the proposed distance outside of the protected contour of an adjacent-channel station. So IEEE 802's proposal (in a 2009 Petition) was to allow antennas above 600 meters HAAT only if more than 68 kilometers outside of the protected contour of a co-channel station, or 426 meters outside of the contour of an adjacent-channel station. Not that those calculations were perfect; sometimes being precise isn't the same as being accurate. TV broadcast interference is usually measured at a fixed height, I think 10 meters above ground. If the antenna is 500m above average terrain, it is probably more than 30 meters above ground. It might even be on a rather tall tower. In that case, the signal level near the ground will not be the same as the signal level in a straight line. So there is probably no likelihood of adjacent-channel interference. I remember an FM station (WMSC) that came on the air around 1970, 2 channels away from two another ones (WKCR, WFUV) whose protected contours it was within. You had to protect second and third adjacent channels, which normally meant 4-channel spacing, because receivers near to the antenna would be clobbered (20dB stronger). In this case the new station was about halfway up an existing 1000-foot TV mast. So its signal strength at the height that counted was so low that it did not violate the interference rules for second and third adjacent channels. It is currently licensed for 1W ERP at 205m HAAT. (But one of the second-adjacent-channel licensees has still given them grief at the FCC.) On 09/30/2010 08:13 PM, Fred Goldstein wrote: At 9/30/2010 10:37 PM, Jack Unger wrote: Fred, I'm sorry to seem dense but I don't understand your explanation below. I'd appreciate it if you would re-explain. The FCC said: transmit antenna used with fixed devices may not be more than 30 meters above the ground. In addition, fixed devices may not be located at sites where the height above average terrain (HAAT) at ground level is more than 76 meters. I'm trying to reconcile that with your statements. Could you please re-explain more clearly or by using better actual numbers (both HAAT at ground level and antenna height above ground)? Thanks in advance, jack Sure. In the Order itself, the FCC explained the origin of the 76 meter HAAT limit. They explained that they didn't want any antennas more than 106 meters AAT. That's the maximum antenna HAAT I referred to. Since antennas are allowed to be 30 meters above ground, they subtracted 30 from 106 and got 75. See paragraph 66 of the Order: We find that limiting the fixed device antenna HAAT to 106 meters (350 feet), as calculated by the TV bands database, provides an appropriate balance of these concerns. We will therefore restrict fixed TV bands devices from operating at locations where the HAAT of the ground is greater than 76 meters; this will allow use of an antenna at a height of up to 30 meters above ground level to provide an antenna HAAT of 106 meters. Accordingly, we are specifying that a fixed TV bands device antenna may not be located at a site where the ground HAAT is greater than 75 meters (246 feet). The Order cited an IEEE 802 Petitition http://fjallfoss.fcc.gov/ecfs/document/view?id=6520201311 which called for HAAT to be a factor. But they didn't call for a ban on operation above 75 meters; rather, they wanted co-channel separation to increase with height: less than 3 meters | 6 km 0.1 km 3 Less than 10 meters* 6.9 km 0.256 km 10 Less than 30 meters 10.8 km 0.285 km 30 Less than 50 meters 13.6 km 0.309 km 50 Less than 75 meters 16.1 km 0.330 km 75 Less than 150 meters 22.6 km 0.372 km 150 Less than 300 meters 32 km 0.405 km 300 Less than 600 meters 45.7 km 0.419 km 600 meters or higher 68 km 0.426 km That's rational. On the other hand I'd prefer allowing fixed devices at any ground elevation, to allow everyone to subscribe, so I'd suggest instead that they maximum ERP be decreased in order to limit interference to the same level. So maybe 6 dB from 76 to 150 meters and 10 dB to 300 meters, though that's a guess; I haven't run the calculations. And I'd allow directional antennas, professionally installed, to have ERP measured in the direction of the protected contour, with no reduction in ERP if it's clear to the distance the above chart. I'm thinking about a petition to that effect. I have real subscriber sites in mind. --
Re: [WISPA] Transmit Antenna Height
Thanks for the explanation. I think I understand it. I have a couple more quick questions. What is the difference between co-channel and adjacent channel? Does that mean if I am more than 68 km from a station I can operate a fixed TVWS Base station at up to 600 meters HAAT? - Matt On 10/01/2010 11:56 AM, Fred Goldstein wrote: At 10/1/2010 02:27 PM, Matt Jenkins wrote: What are the headings for your chart? I don't understand it Eudora had trouble with cut-and-paste of the original document. The first column is height above average terrain, from x to y meters (10 but less than 30, from 30 but less than 50...). The second is the proposed distance outside of the protected contour of a co-channel station. THe second (the small distance) is the proposed distance outside of the protected contour of an adjacent-channel station. So IEEE 802's proposal (in a 2009 Petition) was to allow antennas above 600 meters HAAT only if more than 68 kilometers outside of the protected contour of a co-channel station, or 426 meters outside of the contour of an adjacent-channel station. Not that those calculations were perfect; sometimes being precise isn't the same as being accurate. TV broadcast interference is usually measured at a fixed height, I think 10 meters above ground. If the antenna is 500m above average terrain, it is probably more than 30 meters above ground. It might even be on a rather tall tower. In that case, the signal level near the ground will not be the same as the signal level in a straight line. So there is probably no likelihood of adjacent-channel interference. I remember an FM station (WMSC) that came on the air around 1970, 2 channels away from two another ones (WKCR, WFUV) whose protected contours it was within. You had to protect second and third adjacent channels, which normally meant 4-channel spacing, because receivers near to the antenna would be clobbered (20dB stronger). In this case the new station was about halfway up an existing 1000-foot TV mast. So its signal strength at the height that counted was so low that it did not violate the interference rules for second and third adjacent channels. It is currently licensed for 1W ERP at 205m HAAT. (But one of the second-adjacent-channel licensees has still given them grief at the FCC.) On 09/30/2010 08:13 PM, Fred Goldstein wrote: At 9/30/2010 10:37 PM, Jack Unger wrote: Fred, I'm sorry to seem dense but I don't understand your explanation below. I'd appreciate it if you would re-explain. The FCC said: "transmit antenna used with fixed devices may not be more than 30 meters above the ground. In addition, fixed devices may not be located at sites where the height above average terrain (HAAT) at ground level is more than 76 meters". I'm trying to reconcile that with your statements. Could you please re-explain more clearly or by using better actual numbers (both HAAT at ground level and antenna height above ground)? Thanks in advance, jack Sure. In the Order itself, the FCC explained the origin of the 76 meter HAAT limit. They explained that they didn't want any antennas more than 106 meters AAT. That's the maximum antenna HAAT I referred to. Since antennas are allowed to be 30 meters above ground, they subtracted 30 from 106 and got 75. See paragraph 66 of the Order: "We find that limiting the fixed device antenna HAAT to 106 meters (350 feet), as calculated by the TV bands database, provides an appropriate balance of these concerns. We will therefore restrict fixed TV bands devices from operating at locations where the HAAT of the ground is greater than 76 meters; this will allow use of an antenna at a height of up to 30 meters above ground level to provide an antenna HAAT of 106 meters. Accordingly, we are specifying that a fixed TV bands device antenna may not be located at a site where the ground HAAT is greater than 75 meters (246 feet)." The Order cited an IEEE 802 Petitition http://fjallfoss.fcc.gov/ecfs/document/view?id=6520201311 which called for HAAT to be a factor. But they didn't call for a ban on operation above 75 meters; rather, they wanted co-channel separation to increase with height: less than 3 meters | 6 km 0.1 km 3 Less than 10 meters* 6.9 km 0.256 km 10 Less than 30 meters 10.8 km 0.285 km 30 Less than 50 meters 13.6 km 0.309 km 50 Less than 75 meters 16.1 km 0.330 km 75 Less than 150 meters 22.6 km 0.372 km 150 Less than 300 meters 32 km 0.405 km 300 Less than 600 meters 45.7 km 0.419 km 600 meters or higher 68 km 0.426 km That's rational. On the other hand I'd prefer allowing fixed devices at any ground elevation, to allow everyone to subscribe, so I'd suggest instead that they maximum ERP be decreased in order to limit interference to the same level. So maybe 6 dB from 76 to 150 meters and 10 dB to 300 meters, though that's a guess; I haven't run the calculations. And
Re: [WISPA] Transmit Antenna Height
At 10/1/2010 03:18 PM, Matt Jenkins wrote: Thanks for the explanation. I think I understand it. I have a couple more quick questions. What is the difference between co-channel and adjacent channel? Co-channel means the same frequency, so if you're on channel 31, you're protecting a channel 31. The adjacent channel rules assume a certain amount of receiver selectivity. Does that mean if I am more than 68 km from a station I can operate a fixed TVWS Base station at up to 600 meters HAAT? No. This was what IEEE 802 proposed. The FCC's Order referenced it, and then simply said that the maximum ground HAAT was 75 meters, full stop. Such is the difference between engineers playing with formulas and lawyers in a hurry to draft something that they barely understand while making political compromises. - Matt On 10/01/2010 11:56 AM, Fred Goldstein wrote: At 10/1/2010 02:27 PM, Matt Jenkins wrote: What are the headings for your chart? I don't understand it Eudora had trouble with cut-and-paste of the original document. The first column is height above average terrain, from x to y meters (10 but less than 30, from 30 but less than 50...). The second is the proposed distance outside of the protected contour of a co-channel station. THe second (the small distance) is the proposed distance outside of the protected contour of an adjacent-channel station. So IEEE 802's proposal (in a 2009 Petition) was to allow antennas above 600 meters HAAT only if more than 68 kilometers outside of the protected contour of a co-channel station, or 426 meters outside of the contour of an adjacent-channel station. Not that those calculations were perfect; sometimes being precise isn't the same as being accurate. TV broadcast interference is usually measured at a fixed height, I think 10 meters above ground. If the antenna is 500m above average terrain, it is probably more than 30 meters above ground. It might even be on a rather tall tower. In that case, the signal level near the ground will not be the same as the signal level in a straight line. So there is probably no likelihood of adjacent-channel interference. I remember an FM station (WMSC) that came on the air around 1970, 2 channels away from two another ones (WKCR, WFUV) whose protected contours it was within. You had to protect second and third adjacent channels, which normally meant 4-channel spacing, because receivers near to the antenna would be clobbered (20dB stronger). In this case the new station was about halfway up an existing 1000-foot TV mast. So its signal strength at the height that counted was so low that it did not violate the interference rules for second and third adjacent channels. It is currently licensed for 1W ERP at 205m HAAT. (But one of the second-adjacent-channel licensees has still given them grief at the FCC.) On 09/30/2010 08:13 PM, Fred Goldstein wrote: At 9/30/2010 10:37 PM, Jack Unger wrote: Fred, I'm sorry to seem dense but I don't understand your explanation below. I'd appreciate it if you would re-explain. The FCC said: transmit antenna used with fixed devices may not be more than 30 meters above the ground. In addition, fixed devices may not be located at sites where the height above average terrain (HAAT) at ground level is more than 76 meters. I'm trying to reconcile that with your statements. Could you please re-explain more clearly or by using better actual numbers (both HAAT at ground level and antenna height above ground)? Thanks in advance, jack Sure. In the Order itself, the FCC explained the origin of the 76 meter HAAT limit. They explained that they didn't want any antennas more than 106 meters AAT. That's the maximum antenna HAAT I referred to. Since antennas are allowed to be 30 meters above ground, they subtracted 30 from 106 and got 75. See paragraph 66 of the Order: We find that limiting the fixed device antenna HAAT to 106 meters (350 feet), as calculated by the TV bands database, provides an appropriate balance of these concerns. We will therefore restrict fixed TV bands devices from operating at locations where the HAAT of the ground is greater than 76 meters; this will allow use of an antenna at a height of up to 30 meters above ground level to provide an antenna HAAT of 106 meters. Accordingly, we are specifying that a fixed TV bands device antenna may not be located at a site where the ground HAAT is greater than 75 meters (246 feet). The Order cited an IEEE 802 Petitition http://fjallfoss.fcc.gov/ecfs/document/view?id=6520201311 which called for HAAT to be a factor. But they didn't call for a ban on operation above 75 meters; rather, they wanted co-channel separation to increase with height: less than 3 meters | 6 km 0.1 km 3 Less than 10 meters* 6.9 km 0.256 km 10 Less than 30 meters 10.8 km 0.285 km 30 Less than 50
Re: [WISPA] Transmit Antenna Height
Does that mean if I am more than 68 km from a station I can operate a fixed TVWS Base station at up to 600 meters HAAT? No. This was what IEEE 802 proposed. The FCC's Order referenced it, and then simply said that the maximum ground HAAT was 75 meters, full stop. Such is the difference between engineers playing with formulas and lawyers in a hurry to draft something that they barely understand while making political compromises. BUMMER! This would have solved my HAAT problem. The nearest station from me is about 70km away. - Matt On 10/01/2010 11:56 AM, Fred Goldstein wrote: At 10/1/2010 02:27 PM, Matt Jenkins wrote: What are the headings for your chart? I don't understand it Eudora had trouble with cut-and-paste of the original document. The first column is height above average terrain, from x to y meters (10 but less than 30, from 30 but less than 50...). The second is the proposed distance outside of the protected contour of a co-channel station. THe second (the small distance) is the proposed distance outside of the protected contour of an adjacent-channel station. So IEEE 802's proposal (in a 2009 Petition) was to allow antennas above 600 meters HAAT only if more than 68 kilometers outside of the protected contour of a co-channel station, or 426 meters outside of the contour of an adjacent-channel station. Not that those calculations were perfect; sometimes being precise isn't the same as being accurate. TV broadcast interference is usually measured at a fixed height, I think 10 meters above ground. If the antenna is 500m above average terrain, it is probably more than 30 meters above ground. It might even be on a rather tall tower. In that case, the signal level near the ground will not be the same as the signal level in a straight line. So there is probably no likelihood of adjacent-channel interference. I remember an FM station (WMSC) that came on the air around 1970, 2 channels away from two another ones (WKCR, WFUV) whose protected contours it was within. You had to protect second and third adjacent channels, which normally meant 4-channel spacing, because receivers near to the antenna would be clobbered (20dB stronger). In this case the new station was about halfway up an existing 1000-foot TV mast. So its signal strength at the height that counted was so low that it did not violate the interference rules for second and third adjacent channels. It is currently licensed for 1W ERP at 205m HAAT. (But one of the second-adjacent-channel licensees has still given them grief at the FCC.) On 09/30/2010 08:13 PM, Fred Goldstein wrote: At 9/30/2010 10:37 PM, Jack Unger wrote: Fred, I'm sorry to seem dense but I don't understand your explanation below. I'd appreciate it if you would re-explain. The FCC said: "transmit antenna used with fixed devices may not be more than 30 meters above the ground. In addition, fixed devices may not be located at sites where the height above average terrain (HAAT) at ground level is more than 76 meters". I'm trying to reconcile that with your statements. Could you please re-explain more clearly or by using better actual numbers (both HAAT at ground level and antenna height above ground)? Thanks in advance, jack Sure. In the Order itself, the FCC explained the origin of the 76 meter HAAT limit. They explained that they didn't want any antennas more than 106 meters AAT. That's the maximum antenna HAAT I referred to. Since antennas are allowed to be 30 meters above ground, they subtracted 30 from 106 and got 75. See paragraph 66 of the Order: "We find that limiting the fixed device antenna HAAT to 106 meters (350 feet), as calculated by the TV bands database, provides an appropriate balance of these concerns. We will therefore restrict fixed TV bands devices from operating at locations where the HAAT of the ground is greater than 76 meters; this will allow use of an antenna at a height of up to 30 meters above ground level to provide an antenna HAAT of 106 meters. Accordingly, we are specifying that a fixed TV bands device antenna may not be located at a site where the ground HAAT is greater than 75 meters (246 feet)." The Order cited an IEEE 802 Petitition http://fjallfoss.fcc.gov/ecfs/document/view?id=6520201311 which called for HAAT to be a factor. But they didn't call for a ban on operation above 75 meters; rather, they wanted co-channel separation to increase with height: less than 3 meters | 6 km 0.1 km 3 Less than 10 meters* 6.9 km 0.256 km 10 Less than 30 meters 10.8 km 0.285 km 30 Less than 50 meters 13.6 km 0.309 km 50 Less than 75 meters 16.1 km 0.330 km 75 Less than 150 meters 22.6 km 0.372 km 150 Less than 300 meters 32 km 0.405 km 300 Less than 600 meters 45.7 km 0.419 km 600 meters or higher 68 km 0.426 km
Re: [WISPA] Transmit Antenna Height
Eudora! Now there is a program I havent seen in years! On Fri, Oct 1, 2010 at 2:56 PM, Fred Goldstein fgoldst...@ionary.comwrote: At 10/1/2010 02:27 PM, Matt Jenkins wrote: What are the headings for your chart? I don't understand it Eudora had trouble with cut-and-paste of the original document. The first column is height above average terrain, from x to y meters (10 but less than 30, from 30 but less than 50...). The second is the proposed distance outside of the protected contour of a co-channel station. THe second (the small distance) is the proposed distance outside of the protected contour of an adjacent-channel station. So IEEE 802's proposal (in a 2009 Petition) was to allow antennas above 600 meters HAAT only if more than 68 kilometers outside of the protected contour of a co-channel station, or 426 meters outside of the contour of an adjacent-channel station. Not that those calculations were perfect; sometimes being precise isn't the same as being accurate. TV broadcast interference is usually measured at a fixed height, I think 10 meters above ground. If the antenna is 500m above average terrain, it is probably more than 30 meters above ground. It might even be on a rather tall tower. In that case, the signal level near the ground will not be the same as the signal level in a straight line. So there is probably no likelihood of adjacent-channel interference. I remember an FM station (WMSC) that came on the air around 1970, 2 channels away from two another ones (WKCR, WFUV) whose protected contours it was within. You had to protect second and third adjacent channels, which normally meant 4-channel spacing, because receivers near to the antenna would be clobbered (20dB stronger). In this case the new station was about halfway up an existing 1000-foot TV mast. So its signal strength at the height that counted was so low that it did not violate the interference rules for second and third adjacent channels. It is currently licensed for 1W ERP at 205m HAAT. (But one of the second-adjacent-channel licensees has still given them grief at the FCC.) On 09/30/2010 08:13 PM, Fred Goldstein wrote: At 9/30/2010 10:37 PM, Jack Unger wrote: Fred, I'm sorry to seem dense but I don't understand your explanation below. I'd appreciate it if you would re-explain. The FCC said: transmit antenna used with fixed devices may not be more than 30 meters above the ground. In addition, fixed devices may not be located at sites where the height above average terrain (HAAT) at ground level is more than 76 meters. I'm trying to reconcile that with your statements. Could you please re-explain more clearly or by using better actual numbers (both HAAT at ground level and antenna height above ground)? Thanks in advance, jack Sure. In the Order itself, the FCC explained the origin of the 76 meter HAAT limit. They explained that they didn't want any antennas more than 106 meters AAT. That's the maximum antenna HAAT I referred to. Since antennas are allowed to be 30 meters above ground, they subtracted 30 from 106 and got 75. See paragraph 66 of the Order: We find that limiting the fixed device antenna HAAT to 106 meters (350 feet), as calculated by the TV bands database, provides an appropriate balance of these concerns. We will therefore restrict fixed TV bands devices from operating at locations where the HAAT of the ground is greater than 76 meters; this will allow use of an antenna at a height of up to 30 meters above ground level to provide an antenna HAAT of 106 meters. Accordingly, we are specifying that a fixed TV bands device antenna may not be located at a site where the ground HAAT is greater than 75 meters (246 feet). The Order cited an IEEE 802 Petitition http://fjallfoss.fcc.gov/ecfs/document/view?id=6520201311 which called for HAAT to be a factor. But they didn't call for a ban on operation above 75 meters; rather, they wanted co-channel separation to increase with height: less than 3 meters | 6 km 0.1 km 3 Less than 10 meters* 6.9 km 0.256 km 10 Less than 30 meters 10.8 km 0.285 km 30 Less than 50 meters 13.6 km 0.309 km 50 Less than 75 meters 16.1 km 0.330 km 75 Less than 150 meters 22.6 km 0.372 km 150 Less than 300 meters 32 km 0.405 km 300 Less than 600 meters 45.7 km 0.419 km 600 meters or higher 68 km 0.426 km That's rational. On the other hand I'd prefer allowing fixed devices at any ground elevation, to allow everyone to subscribe, so I'd suggest instead that they maximum ERP be decreased in order to limit interference to the same level. So maybe 6 dB from 76 to 150 meters and 10 dB to 300 meters, though that's a guess; I haven't run the calculations. And I'd allow directional antennas, professionally installed, to have ERP measured in the direction of the protected contour, with no reduction in ERP
Re: [WISPA] Transmit Antenna Height
At 10/1/2010 05:47 PM, you wrote: Eudora! Now there is a program I havent seen in years! Four years discontinued, there's still nothing as good out there to replace it (on Windows). On Fri, Oct 1, 2010 at 2:56 PM, Fred Goldstein mailto:fgoldst...@ionary.comfgoldst...@ionary.com wrote: At 10/1/2010 02:27 PM, Matt Jenkins wrote: What are the headings for your chart? I don't understand it Eudora had trouble with cut-and-paste of the original document. The first column is height above average terrain, from x to y meters (10 but less than 30, from 30 but less than 50...). The second is the proposed distance outside of the protected contour of a co-channel station. THe second (the small distance) is the proposed distance outside of the protected contour of an adjacent-channel station. So IEEE 802's proposal (in a 2009 Petition) was to allow antennas above 600 meters HAAT only if more than 68 kilometers outside of the protected contour of a co-channel station, or 426 meters outside of the contour of an adjacent-channel station. Not that those calculations were perfect; sometimes being precise isn't the same as being accurate. TV broadcast interference is usually measured at a fixed height, I think 10 meters above ground. If the antenna is 500m above average terrain, it is probably more than 30 meters above ground. It might even be on a rather tall tower. In that case, the signal level near the ground will not be the same as the signal level in a straight line. So there is probably no likelihood of adjacent-channel interference. I remember an FM station (WMSC) that came on the air around 1970, 2 channels away from two another ones (WKCR, WFUV) whose protected contours it was within. You had to protect second and third adjacent channels, which normally meant 4-channel spacing, because receivers near to the antenna would be clobbered (20dB stronger). In this case the new station was about halfway up an existing 1000-foot TV mast. So its signal strength at the height that counted was so low that it did not violate the interference rules for second and third adjacent channels. It is currently licensed for 1W ERP at 205m HAAT. (But one of the second-adjacent-channel licensees has still given them grief at the FCC.) -- Fred Goldsteink1io fgoldstein at ionary.com ionary Consulting http://www.ionary.com/ +1 617 795 2701 WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] Transmit Antenna Height
Fred, I'm sorry to seem dense but I don't understand your explanation below. I'd appreciate it if you would re-explain. The FCC said: "transmit antenna used with fixed devices may not be more than 30 meters above the ground. In addition, fixed devices may not be located at sites where the height above average terrain (HAAT) atground level is more than 76 meters". I'm trying to reconcile that with your statements. Could you please re-explain more clearly or by using better actual numbers (both HAAT at ground level and antenna height above ground)? Thanks in advance, jack On 9/23/2010 4:48 PM, Fred Goldstein wrote: The rules allow antenna heights up to 30 meters, around 100 feet. One problem with the maximum HAAT limit is that it applies to the ground height, based on having a 30 meter high antenna. In other words, the ruling assumed a maximum antenna HAAT, and then set the ground HAAT to be 30m below that. If somebody's house is 10m below the limit, then a 10m antenna should be legal. (The minimum antenna height went away, since sensing is no longer required. That frankly seems to be the only major improvement in the rules.) Brian From: wireless-boun...@wispa.org [ mailto:wireless-boun...@wispa.org] On Behalf Of Tom DeReggi Sent: Thursday, September 23, 2010 7:32 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Fred Goldstein To: WISPA General List Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum
Re: [WISPA] Transmit Antenna Height
Fred and Jack Antenna Height - Height is restricted to 30 meters above HAAT (height above average terrain) of 76 meters this can be calculated here. »www.fcc.gov/mb/audio/bickel/haat···tor.html http://www.fcc.gov/mb/audio/bickel/haat_calculator.html Where it asks this question (Enter the height (in meters) of the antenna radiation center above mean sea level (RCAMSL)) Enter your site elevation NOT the antenna radiation center because you get to go 30 meters above ground level at that point. ref: Second Memorandum Opinion and Order (paragraph - 66) Frank Frank On 9/30/2010 7:37 PM, Jack Unger wrote: Fred, I'm sorry to seem dense but I don't understand your explanation below. I'd appreciate it if you would re-explain. The FCC said: transmit antenna used with fixed devices may not be more than 30 meters above the ground. In addition, fixed devices may not be located at sites where the height above average terrain (HAAT) at ground level is more than 76 meters. I'm trying to reconcile that with your statements. Could you please re-explain more clearly or by using better actual numbers (both HAAT at ground level and antenna height above ground)? Thanks in advance, jack On 9/23/2010 4:48 PM, Fred Goldstein wrote: The rules allow antenna heights up to 30 meters, around 100 feet. One problem with the maximum HAAT limit is that it applies to the ground height, based on having a 30 meter high antenna. In other words, the ruling assumed a maximum antenna HAAT, and then set the ground HAAT to be 30m below that. If somebody's house is 10m below the limit, then a 10m antenna should be legal. (The minimum antenna height went away, since sensing is no longer required. That frankly seems to be the only major improvement in the rules.) Brian *From:* wireless-boun...@wispa.org [ mailto:wireless-boun...@wispa.org] *On Behalf Of *Tom DeReggi *Sent:* Thursday, September 23, 2010 7:32 PM *To:* WISPA General List *Subject:* Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Fred Goldstein mailto:fgoldst...@ionary.com To: WISPA General List mailto:wireless@wispa.org Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order
Re: [WISPA] Transmit Antenna Height
Excellent explanation. Thanks. Fred and Jack Antenna Height - Height is restricted to 30 meters above HAAT (height above average terrain) of 76 meters this can be calculated here. www.fcc.gov/mb/audio/bickel/haattor.html Where it asks this question (Enter the height (in meters) of the antenna radiation center above mean sea level (RCAMSL)) Enter your site elevation NOT the antenna radiation center because you get to go 30 meters above ground level at that point. ref: Second Memorandum Opinion and Order (paragraph - 66) Frank Frank On 9/30/2010 7:37 PM, Jack Unger wrote: Fred, I'm sorry to seem dense but I don't understand your explanation below. I'd appreciate it if you would re-explain. The FCC said: "transmit antenna used with fixed devices may not be more than 30 meters above the ground. In addition, fixed devices may not be located at sites where the height above average terrain (HAAT) atground level is more than 76 meters". I'm trying to reconcile that with your statements. Could you please re-explain more clearly or by using better actual numbers (both HAAT at ground level and antenna height above ground)? Thanks in advance, jack On 9/23/2010 4:48 PM, Fred Goldstein wrote: The rules allow antenna heights up to 30 meters, around 100 feet. One problem with the maximum HAAT limit is that it applies to the ground height, based on having a 30 meter high antenna. In other words, the ruling assumed a maximum antenna HAAT, and then set the ground HAAT to be 30m below that. If somebody's house is 10m below the limit, then a 10m antenna should be legal. (The minimum antenna height went away, since sensing is no longer required. That frankly seems to be the only major improvement in the rules.) Brian From: wireless-boun...@wispa.org [ mailto:wireless-boun...@wispa.org] On Behalf Of Tom DeReggi Sent: Thursday, September 23, 2010 7:32 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Fred Goldstein To: WISPA General List Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a dec
Re: [WISPA] Transmit Antenna Height
At 9/30/2010 10:37 PM, Jack Unger wrote: Fred, I'm sorry to seem dense but I don't understand your explanation below. I'd appreciate it if you would re-explain. The FCC said: transmit antenna used with fixed devices may not be more than 30 meters above the ground. In addition, fixed devices may not be located at sites where the height above average terrain (HAAT) at ground level is more than 76 meters. I'm trying to reconcile that with your statements. Could you please re-explain more clearly or by using better actual numbers (both HAAT at ground level and antenna height above ground)? Thanks in advance, jack Sure. In the Order itself, the FCC explained the origin of the 76 meter HAAT limit. They explained that they didn't want any antennas more than 106 meters AAT. That's the maximum antenna HAAT I referred to. Since antennas are allowed to be 30 meters above ground, they subtracted 30 from 106 and got 75. See paragraph 66 of the Order: We find that limiting the fixed device antenna HAAT to 106 meters (350 feet), as calculated by the TV bands database, provides an appropriate balance of these concerns. We will therefore restrict fixed TV bands devices from operating at locations where the HAAT of the ground is greater than 76 meters; this will allow use of an antenna at a height of up to 30 meters above ground level to provide an antenna HAAT of 106 meters. Accordingly, we are specifying that a fixed TV bands device antenna may not be located at a site where the ground HAAT is greater than 75 meters (246 feet). The Order cited an IEEE 802 Petitition http://fjallfoss.fcc.gov/ecfs/document/view?id=6520201311 which called for HAAT to be a factor. But they didn't call for a ban on operation above 75 meters; rather, they wanted co-channel separation to increase with height: less than 3 meters | 6 km 0.1 km 3 Less than 10 meters* 6.9 km 0.256 km 10 Less than 30 meters 10.8 km 0.285 km 30 Less than 50 meters 13.6 km 0.309 km 50 Less than 75 meters 16.1 km 0.330 km 75 Less than 150 meters 22.6 km 0.372 km 150 Less than 300 meters 32 km 0.405 km 300 Less than 600 meters 45.7 km 0.419 km 600 meters or higher 68 km 0.426 km That's rational. On the other hand I'd prefer allowing fixed devices at any ground elevation, to allow everyone to subscribe, so I'd suggest instead that they maximum ERP be decreased in order to limit interference to the same level. So maybe 6 dB from 76 to 150 meters and 10 dB to 300 meters, though that's a guess; I haven't run the calculations. And I'd allow directional antennas, professionally installed, to have ERP measured in the direction of the protected contour, with no reduction in ERP if it's clear to the distance the above chart. I'm thinking about a petition to that effect. I have real subscriber sites in mind. On 9/23/2010 4:48 PM, Fred Goldstein wrote: The rules allow antenna heights up to 30 meters, around 100 feet. One problem with the maximum HAAT limit is that it applies to the ground height, based on having a 30 meter high antenna. In other words, the ruling assumed a maximum antenna HAAT, and then set the ground HAAT to be 30m below that. If somebody's house is 10m below the limit, then a 10m antenna should be legal. (The minimum antenna height went away, since sensing is no longer required. That frankly seems to be the only major improvement in the rules.) Brian From: mailto:wireless-boun...@wispa.orgwireless-boun...@wispa.org [ mailto:wireless-boun...@wispa.org] On Behalf Of Tom DeReggi Sent: Thursday, September 23, 2010 7:32 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: mailto:fgoldst...@ionary.comFred Goldstein To: mailto:wireless@wispa.orgWISPA General List Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters
Re: [WISPA] Transmit Antenna Height
Fred, I think were saying the same thing? On 9/30/2010 8:13 PM, Fred Goldstein wrote: At 9/30/2010 10:37 PM, Jack Unger wrote: Fred, I'm sorry to seem dense but I don't understand your explanation below. I'd appreciate it if you would re-explain. The FCC said: transmit antenna used with fixed devices may not be more than 30 meters above the ground. In addition, fixed devices may not be located at sites where the height above average terrain (HAAT) at ground level is more than 76 meters. I'm trying to reconcile that with your statements. Could you please re-explain more clearly or by using better actual numbers (both HAAT at ground level and antenna height above ground)? Thanks in advance, jack Sure. In the Order itself, the FCC explained the origin of the 76 meter HAAT limit. They explained that they didn't want any antennas more than 106 meters AAT. That's the maximum antenna HAAT I referred to. Since antennas are allowed to be 30 meters above ground, they subtracted 30 from 106 and got 75. See paragraph 66 of the Order: We find that limiting the fixed device antenna HAAT to 106 meters (350 feet), as calculated by the TV bands database, provides an appropriate balance of these concerns. We will therefore restrict fixed TV bands devices from operating at locations where the HAAT of the ground is greater than 76 meters; this will allow use of an antenna at a height of up to 30 meters above ground level to provide an antenna HAAT of 106 meters. Accordingly, we are specifying that a fixed TV bands device antenna may not be located at a site where the ground HAAT is greater than 75 meters (246 feet). The Order cited an IEEE 802 Petitition http://fjallfoss.fcc.gov/ecfs/document/view?id=6520201311 which called for HAAT to be a factor. But they didn't call for a ban on operation above 75 meters; rather, they wanted co-channel separation to increase with height: less than 3 meters | 6 km 0.1 km 3 Less than 10 meters* 6.9 km 0.256 km 10 Less than 30 meters 10.8 km 0.285 km 30 Less than 50 meters 13.6 km 0.309 km 50 Less than 75 meters 16.1 km 0.330 km 75 Less than 150 meters22.6 km 0.372 km 150 Less than 300 meters 32 km 0.405 km 300 Less than 600 meters 45.7 km 0.419 km 600 meters or higher68 km 0.426 km That's rational. On the other hand I'd prefer allowing fixed devices at any ground elevation, to allow everyone to subscribe, so I'd suggest instead that they maximum ERP be decreased in order to limit interference to the same level. So maybe 6 dB from 76 to 150 meters and 10 dB to 300 meters, though that's a guess; I haven't run the calculations. And I'd allow directional antennas, professionally installed, to have ERP measured in the direction of the protected contour, with no reduction in ERP if it's clear to the distance the above chart. I'm thinking about a petition to that effect. I have real subscriber sites in mind. On 9/23/2010 4:48 PM, Fred Goldstein wrote: The rules allow antenna heights up to 30 meters, around 100 feet. One problem with the maximum HAAT limit is that it applies to the ground height, based on having a 30 meter high antenna. In other words, the ruling assumed a maximum antenna HAAT, and then set the ground HAAT to be 30m below that. If somebody's house is 10m below the limit, then a 10m antenna should be legal. (The minimum antenna height went away, since sensing is no longer required. That frankly seems to be the only major improvement in the rules.) Brian *From:* wireless-boun...@wispa.org mailto:wireless-boun...@wispa.org [ mailto:wireless-boun...@wispa.org] *On Behalf Of *Tom DeReggi *Sent:* Thursday, September 23, 2010 7:32 PM *To:* WISPA General List *Subject:* Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Fred Goldstein mailto:fgoldst...@ionary.com To: WISPA General List mailto:wireless@wispa.org Sent: Thursday, September 23, 2010 4:36 PM Subject
Re: [WISPA] Transmit Antenna Height
The actual frequency band has nothing to do with data capacity. The carrier CHANNEL BANDWIDTH is the important number. If a 6 megahertz wide channel is used at say 200-206 MHz then any modulation system used on that carrier should be able to carry the same amount of data as an equivalent channel at say 600-606 MHz. Note both carriers are 6 MHz wide. The capacity of the channel is determined by the spectral efficiency of the system used to modulate and demodulate the information from the channel's carrier(s). Do a Google search on Nyquist / Shannon's Law / maximum bits per hertz to get a more thorough understanding of the concepts. What we see in most of the current systems we use for fixed wireless broadband are spectral efficiencies from 0.5 to 10 bits per hertz. Some estimates say that we will see roughly 17 bits per hertz from WiMAX and LTE deployments in the coming months / years. This in large part due to the advancements from MIMO which allows for in-channel reuse of the carrier bandwidth. John Scrivner On Sat, Sep 25, 2010 at 5:42 PM, Scott Reed scottr...@onlyinternet.net wrote: That is not exactly true. Depends on the modulation techniques. And I believe there is an upper limit to the number of bits you can get on a single cycle of the carrier. On 9/25/2010 10:32 AM, Mike Hammett wrote: Just as fast as any other frequency. - Mike Hammett Intelligent Computing Solutions http://www.ics-il.com On 9/24/2010 5:50 PM, RickG wrote: But how fast can 200 or 300MHz go? On Thu, Sep 23, 2010 at 7:41 PM, Brian Webster bwebs...@wirelessmapping.com wrote: But what if you are able to use spectrum around 200 or 300 MHz? That certainly goes through trees. Brian From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Tom DeReggi Sent: Thursday, September 23, 2010 7:32 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Fred Goldstein To: WISPA General List Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission’s stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit
Re: [WISPA] Transmit Antenna Height
http://en.wikipedia.org/wiki/Spectral_efficiency#Comparison_table Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Sun, Sep 26, 2010 at 2:03 PM, John Scrivner j...@scrivner.com wrote: The actual frequency band has nothing to do with data capacity. The carrier CHANNEL BANDWIDTH is the important number. If a 6 megahertz wide channel is used at say 200-206 MHz then any modulation system used on that carrier should be able to carry the same amount of data as an equivalent channel at say 600-606 MHz. Note both carriers are 6 MHz wide. The capacity of the channel is determined by the spectral efficiency of the system used to modulate and demodulate the information from the channel's carrier(s). Do a Google search on Nyquist / Shannon's Law / maximum bits per hertz to get a more thorough understanding of the concepts. What we see in most of the current systems we use for fixed wireless broadband are spectral efficiencies from 0.5 to 10 bits per hertz. Some estimates say that we will see roughly 17 bits per hertz from WiMAX and LTE deployments in the coming months / years. This in large part due to the advancements from MIMO which allows for in-channel reuse of the carrier bandwidth. John Scrivner On Sat, Sep 25, 2010 at 5:42 PM, Scott Reed scottr...@onlyinternet.net wrote: That is not exactly true. Depends on the modulation techniques. And I believe there is an upper limit to the number of bits you can get on a single cycle of the carrier. On 9/25/2010 10:32 AM, Mike Hammett wrote: Just as fast as any other frequency. - Mike Hammett Intelligent Computing Solutions http://www.ics-il.com On 9/24/2010 5:50 PM, RickG wrote: But how fast can 200 or 300MHz go? On Thu, Sep 23, 2010 at 7:41 PM, Brian Webster bwebs...@wirelessmapping.com wrote: But what if you are able to use spectrum around 200 or 300 MHz? That certainly goes through trees. Brian From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Tom DeReggi Sent: Thursday, September 23, 2010 7:32 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Fred Goldstein To: WISPA General List Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize
Re: [WISPA] Transmit Antenna Height
Just as fast as any other frequency. - Mike Hammett Intelligent Computing Solutions http://www.ics-il.com On 9/24/2010 5:50 PM, RickG wrote: But how fast can 200 or 300MHz go? On Thu, Sep 23, 2010 at 7:41 PM, Brian Webster bwebs...@wirelessmapping.com mailto:bwebs...@wirelessmapping.com wrote: But what if you are able to use spectrum around 200 or 300 MHz? That certainly goes through trees. Brian *From:* wireless-boun...@wispa.org mailto:wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org mailto:wireless-boun...@wispa.org] *On Behalf Of *Tom DeReggi *Sent:* Thursday, September 23, 2010 7:32 PM *To:* WISPA General List *Subject:* Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - *From:* Fred Goldstein mailto:fgoldst...@ionary.com *To:* WISPA General List mailto:wireless@wispa.org *Sent:* Thursday, September 23, 2010 4:36 PM *Subject:* Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. /Decision. /We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the /Second Report and Order/, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission’s stated approach in the /Second Report and Order /of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners’ concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point such as a hill or mountain.130 In such cases, the distance at which a TV bands device signal could propagate would be significantly increased, thus increasing the potential for interference to authorized operations
Re: [WISPA] Transmit Antenna Height
That is not exactly true. Depends on the modulation techniques. And I believe there is an upper limit to the number of bits you can get on a single cycle of the carrier. On 9/25/2010 10:32 AM, Mike Hammett wrote: Just as fast as any other frequency. - Mike Hammett Intelligent Computing Solutions http://www.ics-il.com On 9/24/2010 5:50 PM, RickG wrote: But how fast can 200 or 300MHz go? On Thu, Sep 23, 2010 at 7:41 PM, Brian Webster bwebs...@wirelessmapping.com mailto:bwebs...@wirelessmapping.com wrote: But what if you are able to use spectrum around 200 or 300 MHz? That certainly goes through trees. Brian *From:* wireless-boun...@wispa.org mailto:wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org mailto:wireless-boun...@wispa.org] *On Behalf Of *Tom DeReggi *Sent:* Thursday, September 23, 2010 7:32 PM *To:* WISPA General List *Subject:* Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - *From:* Fred Goldstein mailto:fgoldst...@ionary.com *To:* WISPA General List mailto:wireless@wispa.org *Sent:* Thursday, September 23, 2010 4:36 PM *Subject:* Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. /Decision. /We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the /Second Report and Order/, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission’s stated approach in the /Second Report and Order /of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners’ concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point such as a hill
Re: [WISPA] Transmit Antenna Height
Yeah... that will help. In my neck of the woods, its possible the only available channels might be in the lower channels anyway. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Brian Webster To: 'WISPA General List' Sent: Thursday, September 23, 2010 7:41 PM Subject: Re: [WISPA] Transmit Antenna Height But what if you are able to use spectrum around 200 or 300 MHz? That certainly goes through trees. Brian From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Tom DeReggi Sent: Thursday, September 23, 2010 7:32 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Fred Goldstein To: WISPA General List Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners' concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point such as a hill or mountain.130 In such cases, the distance at which a TV bands device signal could propagate would be significantly increased, thus increasing the potential for interference to authorized operations in the TV bands. We therefore conclude that it is necessary to modify our rules to limit the antenna HAAT of a fixed device as well as its antenna height above ground. In considering a limit for antenna HAAT, we need to balance the concerns for long range propagation from high points against the typical variability of ground height that occurs in areas where there are significant local high points - we do not want
Re: [WISPA] Transmit Antenna Height
There is one other benefit of this No body else will be able to install higher either. Mounting lower to the ground, its more likely a WISP will be able to install their own tower, and no longer have to pay huge colocation costs on a commercial tower. I predict more houses up on the hill, being the new TVWhitespace towers. Although, aren't these low channel Whitespace omnis like giant, and weight a ton? Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Brian Webster To: 'WISPA General List' Sent: Thursday, September 23, 2010 7:41 PM Subject: Re: [WISPA] Transmit Antenna Height But what if you are able to use spectrum around 200 or 300 MHz? That certainly goes through trees. Brian From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Tom DeReggi Sent: Thursday, September 23, 2010 7:32 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Fred Goldstein To: WISPA General List Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners' concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point such as a hill or mountain.130 In such cases, the distance at which a TV bands device signal could propagate would be significantly increased, thus increasing the potential for interference to authorized operations in the TV bands. We therefore conclude that it is necessary to modify our rules to limit the antenna HAAT of a fixed device as well as its
Re: [WISPA] Transmit Antenna Height
At 9/24/2010 02:16 PM, Tom DeReggi wrote: There is one other benefit of this No body else will be able to install higher either. Mounting lower to the ground, its more likely a WISP will be able to install their own tower, and no longer have to pay huge colocation costs on a commercial tower. I predict more houses up on the hill, being the new TVWhitespace towers. Although, aren't these low channel Whitespace omnis like giant, and weight a ton? No, Tom, you missed the poison pill. If somebody lives on a hill, more than 76 meters above average terrain, then they are banned from using fixed whitespace devices AT ALL. Not at 4W. Not at 1W. Just the flea-power portable devices, which are basically wireless mics. This new rule needs to be changed. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: mailto:bwebs...@wirelessmapping.comBrian Webster To: mailto:wireless@wispa.org'WISPA General List' Sent: Thursday, September 23, 2010 7:41 PM Subject: Re: [WISPA] Transmit Antenna Height But what if you are able to use spectrum around 200 or 300 MHz? That certainly goes through trees. Brian From: mailto:wireless-boun...@wispa.orgwireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Tom DeReggi Sent: Thursday, September 23, 2010 7:32 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: mailto:fgoldst...@ionary.comFred Goldstein To: mailto:wireless@wispa.orgWISPA General List Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners' concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point
Re: [WISPA] Transmit Antenna Height
Those were my thoughts as well. If anyone can adapt quickly to this decision on tower heights, it will be innovative WISPs. Rick From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Tom DeReggi Sent: Friday, September 24, 2010 2:16 PM To: bwebs...@wirelessmapping.com; WISPA General List Subject: Re: [WISPA] Transmit Antenna Height There is one other benefit of this No body else will be able to install higher either. Mounting lower to the ground, its more likely a WISP will be able to install their own tower, and no longer have to pay huge colocation costs on a commercial tower. I predict more houses up on the hill, being the new TVWhitespace towers. Although, aren't these low channel Whitespace omnis like giant, and weight a ton? Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Brian Webster mailto:bwebs...@wirelessmapping.com To: 'WISPA General mailto:wireless@wispa.org List' Sent: Thursday, September 23, 2010 7:41 PM Subject: Re: [WISPA] Transmit Antenna Height But what if you are able to use spectrum around 200 or 300 MHz? That certainly goes through trees. Brian From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Tom DeReggi Sent: Thursday, September 23, 2010 7:32 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Fred mailto:fgoldst...@ionary.com Goldstein To: WISPA General List mailto:wireless@wispa.org Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners' concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point
Re: [WISPA] Transmit Antenna Height
But how fast can 200 or 300MHz go? On Thu, Sep 23, 2010 at 7:41 PM, Brian Webster bwebs...@wirelessmapping.com wrote: But what if you are able to use spectrum around 200 or 300 MHz? That certainly goes through trees. Brian *From:* wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] *On Behalf Of *Tom DeReggi *Sent:* Thursday, September 23, 2010 7:32 PM *To:* WISPA General List *Subject:* Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - *From:* Fred Goldstein fgoldst...@ionary.com *To:* WISPA General List wireless@wispa.org *Sent:* Thursday, September 23, 2010 4:36 PM *Subject:* Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. *Decision. *We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the *Second Report and Order*, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission’s stated approach in the *Second Report and Order *of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners’ concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point such as a hill or mountain.130 In such cases, the distance at which a TV bands device signal could propagate would be significantly increased, thus increasing the potential for interference to authorized operations in the TV bands. We therefore conclude that it is necessary to modify our rules to limit the antenna HAAT of a fixed device as well as its antenna height above ground. In considering a limit for antenna HAAT, we need to balance the concerns for long range propagation from high points against the typical variability of ground height that occurs in areas where there are significant local high points – we do not want to preclude fixed devices from a large number of sites in areas where there are rolling hills or a large number of relatively high points that do not generally provide open, line-of-sight paths for propagation over long distances. We find that limiting the fixed device antenna HAAT
Re: [WISPA] Transmit Antenna Height
I did a HAAT for my sites where I would use this. The results Antenna elevation above sea level : 1096.27m Average ground elevation above sea level: 1216.56m HAAT: -120.28998046875m(5m antenna) Antenna elevation above sea level : 1192.39m Average ground elevation above sea level: 1449.41m HAAT: -257.019985351563m (5m antenna) So, is the HAAT limit a positive one, or a absolute one? Doing the HAAT for client side are also all negative numbers but 100 meters less on average. I do not know if this means I could use 700ws or not, assuming there was free channels. On Fri, Sep 24, 2010 at 2:03 PM, Brian Webster bwebs...@wirelessmapping.com wrote: Fred, Have you actually studied some locations that might be in this situation and computed the HAAT using the tool on the FCC web site or some other HAAT calculation tool? If you look at a calculation for a site such as my office which is at 1420 above sea level and the valley floors around me typically at around 1170 AMSL, my location still has a negative HAAT of 47 meters even using a 10 meter antenna height! This is because there are other hills around me that are at my elevation or taller out each radial to 16km. I have pasted the text of a HAAT report from Radio Mobile so you get an idea of how the calculations are run. I believe you said you are in Western Mass. Your terrain is not much unlike my part of upstate NY. You can paste my address in to Google Maps and turn the terrain feature on to get an idea of the terrain around me. Unless your client is actually at the top of the highest peak within 16 KM of itself, there is a high likelihood that the HAAT will be within the limits and possibly at a negative number Brian 214 Eggleston Hill Rd. Cooperstown, NY 13326 Height Above Average Terrain Report generated at 4:57:42 PM , 9/24/2010 Antenna geographic coordinates 42°36'04N,074°55'37W FN22MO Ground elevation: 436.5m Antenna height above ground: 10m Azt(°) D(km) Ground elevation(m) 000 03.00 0508.1 000 03.26 0529.2 000 03.52 0548.8 000 03.78 0569.6 000 04.04 0581.2 000 04.30 0590.4 000 04.56 0590.8 000 04.82 0606.3 000 05.08 0590.9 000 05.34 0547.3 000 05.60 0513.9 000 05.86 0482.1 000 06.12 0447.3 000 06.38 0408.5 000 06.64 0405.3 000 06.90 0389.6 000 07.16 0388.0 000 07.42 0398.1 000 07.68 0406.3 000 07.94 0424.9 000 08.20 0447.0 000 08.46 0443.0 000 08.72 0393.4 000 08.98 0369.4 000 09.24 0371.1 000 09.50 0377.5 000 09.76 0375.8 000 10.02 0365.6 000 10.28 0363.9 000 10.54 0377.0 000 10.80 0377.0 000 11.06 0375.2 000 11.32 0372.7 000 11.58 0363.9 000 11.84 0362.0 000 12.10 0364.4 000 12.36 0376.9 000 12.62 0379.1 000 12.88 0373.0 000 13.14 0370.7 000 13.40 0378.3 000 13.66 0380.6 000 13.92 0394.0 000 14.18 0388.5 000 14.44 0423.8 000 14.70 0440.4 000 14.96 0431.8 000 15.22 0429.5 000 15.48 0431.9 000 15.74 0430.2 000 16.00 0432.9 000 Average 433.08m 000 HAAT 13.42m 045 03.00 0451.4 045 03.26 0420.8 045 03.52 0397.6 045 03.78 0370.2 045 04.04 0368.5 045 04.30 0363.9 045 04.56 0365.0 045 04.82 0361.4 045 05.08 0360.0 045 05.34 0367.0 045 05.60 0378.3 045 05.86 0379.8 045 06.12 0387.5 045 06.38 0428.0 045 06.64 0438.8 045 06.90 0408.4 045 07.16 0430.0 045 07.42 0434.8 045 07.68 0474.9 045 07.94 0514.4 045 08.20 0519.7 045 08.46 0523.5 045 08.72 0498.6 045 08.98 0464.7 045 09.24 0492.5 045 09.50 0516.1 045 09.76 0541.8 045 10.02 0533.7 045 10.28 0525.6 045 10.54 0537.8 045 10.80 0555.9 045 11.06
Re: [WISPA] Transmit Antenna Height
At 9/24/2010 05:03 PM, Brian Webster wrote: Fred, Have you actually studied some locations that might be in this situation and computed the HAAT using the tool on the FCC web site or some other HAAT calculation tool? If you look at a calculation for a site such as my office which is at 1420 above sea level and the valley floors around me typically at around 1170 AMSL, my location still has a negative HAAT of 47 meters even using a 10 meter antenna height! This is because there are other hills around me that are at my elevation or taller out each radial to 16km. I have pasted the text of a HAAT report from Radio Mobile so you get an idea of how the calculations are run. I believe you said you are in Western Mass. Your terrain is not much unlike my part of upstate NY. You can paste my address in to Google Maps and turn the terrain feature on to get an idea of the terrain around me. Unless your client is actually at the top of the highest peak within 16 KM of itself, there is a high likelihood that the HAAT will be within the limits and possibly at a negative number Yes, I actually used RadioMobile's HAAT calculator. I recently did a study on five towns in Western MA. (It's not where I am, but I designed some stimulus fiber that's about to be built there, so I wanted to see what a WISP could do with it, since that's what it was designed for.) Two of the towns are mostly valley; the houses aren't on the high ground. In those two towns, a few areas with homes were still 75m AAT, but they're fairly small. In three towns, big sections of town were excluded. One lost the town center (that's why it's called a hill town). One lost the school, the nearby neighborhood, and a couple of other population clusters representing, all told, a big part of the town. The third lost part of the town center and a couple of outlying neighborhoods -- there's a big American Tower site near the center, which is the best place for an access point, but some homes down the hill are still in the banned zone. 75 meters is not very high when the local terrain varies by about a thousand feet. You don't need to be on top of the hill, just have the valleys in your eight radials. Brian 214 Eggleston Hill Rd. Cooperstown, NY 13326 Height Above Average Terrain Report generated at 4:57:42 PM , 9/24/2010 Antenna geographic coordinates 42°36'04N,074°55'37W FN22MO Ground elevation: 436.5m Antenna height above ground: 10m Azt(°)D(km) Ground elevation(m) 000 03.00 0508.1 000 03.26 0529.2 000 03.52 0548.8 000 03.78 0569.6 000 04.04 0581.2 000 04.30 0590.4 000 04.56 0590.8 000 04.82 0606.3 000 05.08 0590.9 000 05.34 0547.3 000 05.60 0513.9 000 05.86 0482.1 000 06.12 0447.3 000 06.38 0408.5 000 06.64 0405.3 000 06.90 0389.6 000 07.16 0388.0 000 07.42 0398.1 000 07.68 0406.3 000 07.94 0424.9 000 08.20 0447.0 000 08.46 0443.0 000 08.72 0393.4 000 08.98 0369.4 000 09.24 0371.1 000 09.50 0377.5 000 09.76 0375.8 000 10.02 0365.6 000 10.28 0363.9 000 10.54 0377.0 000 10.80 0377.0 000 11.06 0375.2 000 11.32 0372.7 000 11.58 0363.9 000 11.84 0362.0 000 12.10 0364.4 000 12.36 0376.9 000 12.62 0379.1 000 12.88 0373.0 000 13.14 0370.7 000 13.40 0378.3 000 13.66 0380.6 000 13.92 0394.0 000 14.18 0388.5 000 14.44 0423.8 000 14.70 0440.4 000 14.96 0431.8 000 15.22 0429.5 000 15.48 0431.9 000 15.74 0430.2 000 16.00 0432.9 000 Average 433.08m 000 HAAT 13.42m 045 03.00 0451.4 045 03.26 0420.8 045 03.52 0397.6 045 03.78 0370.2 045 04.04 0368.5 045 04.30 0363.9 045 04.56 0365.0 045 04.82 0361.4 045 05.08 0360.0 045 05.34 0367.0 045 05.60 0378.3 045 05.86 0379.8 045 06.12 0387.5 045 06.38 0428.0 045 06.64 0438.8 045 06.90 0408.4 045 07.16 0430.0 045 07.42 0434.8 045 07.68 0474.9 045 07.94 0514.4 045 08.20 0519.7 045 08.46 0523.5 045 08.72 0498.6 045 08.98 0464.7 045 09.24 0492.5 045
[WISPA] Transmit Antenna Height
65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners' concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point such as a hill or mountain.130 In such cases, the distance at which a TV bands device signal could propagate would be significantly increased, thus increasing the potential for interference to authorized operations in the TV bands. We therefore conclude that it is necessary to modify our rules to limit the antenna HAAT of a fixed device as well as its antenna height above ground. In considering a limit for antenna HAAT, we need to balance the concerns for long range propagation from high points against the typical variability of ground height that occurs in areas where there are significant local high points - we do not want to preclude fixed devices from a large number of sites in areas where there are rolling hills or a large number of relatively high points that do not generally provide open, line-of-sight paths for propagation over long distances. We find that limiting the fixed device antenna HAAT to 106 meters (350 feet), as calculated by the TV bands database, provides an appropriate balance of these concerns. We will therefore restrict fixed TV bands devices from operating at locations where the HAAT of the ground is greater than 76 meters; this will allow use of an antenna at a height of up to 30 meters above ground level to provide an antenna HAAT of 106 meters. Accordingly, we are specifying that a fixed TV bands device antenna may not be located at a site where the ground HAAT is greater than 75 meters (246 feet). The ground HAAT is to be calculated by the TV bands database using computational software employing the methodology in Section 73.684(d) of the rules to ensure that fixed devices comply with this requirement. 130 The antenna height above ground is the distance from the antenna center of radiation to the actual ground directly below the antenna. To calculate the antenna height above average terrain (HAAT), the average elevation of the surrounding terrain above mean sea level must be determined along at least 8 evenly spaced radials at distances from 3 to 16 km from the transmitter site. The HAAT is the difference between the antenna height above mean sea level (the antenna height above ground plus the site elevation) and the average elevation of the surrounding terrain. 67. In reexamining this issue, we also note that the rules currently do not indicate that fixed device antenna heights must be provided to the database for use in determining available channels. It was clearly the Commission's intent that fixed devices include their height when querying the database because the available channels for fixed devices cannot be determined without this information.131 We are therefore modifying Sections 15.711(b)(3) and 15.713(f)(3) to indicate that fixed devices must submit their antenna height above ground to the database. 68. We continue to decline to establish height limits for personal/portable devices. As the Commission stated in the Second Report and Order, there is no practical way to enforce such limits, and such limits are not necessary due to the different technical and operational characteristics of personal/portable devices. Respectfully, Rick Harnish Executive Director WISPA 260-307-4000 cell 866-317-2851 WISPA Office Skype: rick.harnish. rharn...@wispa.org WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] Transmit Antenna Height
This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners' concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point such as a hill or mountain.130 In such cases, the distance at which a TV bands device signal could propagate would be significantly increased, thus increasing the potential for interference to authorized operations in the TV bands. We therefore conclude that it is necessary to modify our rules to limit the antenna HAAT of a fixed device as well as its antenna height above ground. In considering a limit for antenna HAAT, we need to balance the concerns for long range propagation from high points against the typical variability of ground height that occurs in areas where there are significant local high points we do not want to preclude fixed devices from a large number of sites in areas where there are rolling hills or a large number of relatively high points that do not generally provide open, line-of-sight paths for propagation over long distances. We find that limiting the fixed device antenna HAAT to 106 meters (350 feet), as calculated by the TV bands database, provides an appropriate balance of these concerns. We will therefore restrict fixed TV bands devices from operating at locations where the HAAT of the ground is greater than 76 meters; this will allow use of an antenna at a height of up to 30 meters above ground level to provide an antenna HAAT of 106 meters. Accordingly, we are specifying that a fixed TV bands device antenna may not be located at a site where the ground HAAT is greater than 75 meters (246 feet). The ground HAAT is to be calculated by the TV bands database using computational software employing the methodology in Section 73.684(d) of the rules to ensure that fixed devices comply with this requirement. 130 The antenna height above ground is the distance from the antenna center of radiation to the actual ground directly below the antenna. To calculate the antenna height above average terrain (HAAT), the average elevation of the surrounding terrain above mean sea level must be determined along at least 8 evenly spaced radials at distances from 3 to 16 km from the transmitter site. The HAAT is the difference between the antenna height above mean sea level (the antenna height above ground plus the site elevation) and the average elevation of the surrounding terrain. 67. In reexamining this issue, we also note that the rules currently do not indicate that fixed device antenna heights must be provided to the database for use in determining available channels. It was
Re: [WISPA] Transmit Antenna Height
If you are on a high mountain and there are also a lot of other high locations around you your HAAT number could still be low. If however you are on a high mountain and the rest of the area all the way around your site is much lower, your HAAT figure will go up. Sites built on side hill locations with the hill rising above in part of the radius will greatly reduce the HAAT number. http://www.fcc.gov/mb/audio/bickel/haat_calculator.html How is the HAAT determined? A HAAT value is determined by taking 50 evenly spaced elevation points (above mean sea level [AMSL]) along at least 8 evenly spaced radials from the transmitter site (starting at 0 degrees [True North]). The 50 evenly spaced points are sampled in the segment between 3 to 16 km (formerly 2 to 10 miles) along each radial. The elevation points along each radial are averaged, then the radial averages are averaged to provide the final HAAT value. Terrain variations within 3 km (2 miles) of the transmitter site usually do not have a great impact on station coverage. Brian From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Fred Goldstein Sent: Thursday, September 23, 2010 4:36 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners' concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point such as a hill or mountain.130 In such cases, the distance at which a TV bands device signal could propagate would be significantly increased, thus increasing the potential for interference to authorized operations in the TV bands. We therefore conclude that it is necessary to modify our rules to limit the antenna HAAT of a fixed device as well as its antenna height above ground. In considering a limit for antenna HAAT, we need to balance the concerns for long range propagation from high points against the typical variability of ground height that occurs in areas where there are significant local high points - we do not want to preclude fixed devices from a large number of sites in areas where there are rolling hills or a large number of relatively high points that do not generally provide open, line-of-sight paths for propagation over long distances. We find that limiting the fixed device antenna HAAT to 106 meters (350 feet), as calculated by the TV bands database, provides an appropriate balance of these concerns. We will therefore restrict fixed TV bands devices from operating at locations where the HAAT of the ground is greater than 76 meters; this will allow use of an antenna at a height of up
Re: [WISPA] Transmit Antenna Height
They listed all fixed devices must be below 75 meters HAAT. A lot of customers fixed CPE could be well above that as well. On 09/23/2010 01:50 PM, Brian Webster wrote: If you are on a high mountain and there are also a lot of other high locations around you your HAAT number could still be low. If however you are on a high mountain and the rest of the area all the way around your site is much lower, your HAAT figure will go up. Sites built on side hill locations with the hill rising above in part of the radius will greatly reduce the HAAT number. http://www.fcc.gov/mb/audio/bickel/haat_calculator.html How is the HAAT determined? A HAAT value is determined by taking 50 evenly spaced elevation points (above mean sea level [AMSL]) along at least 8 evenly spaced radials from the transmitter site (starting at 0 degrees [True North]). The 50 evenly spaced points are sampled in the segment between 3 to 16 km (formerly 2 to 10 miles) along each radial. The elevation points along each radial are averaged, then the radial averages are averaged to provide the final HAAT value. Terrain variations within 3 km (2 miles) of the transmitter site usually do not have a great impact on station coverage. Brian *From:* wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] *On Behalf Of *Fred Goldstein *Sent:* Thursday, September 23, 2010 4:36 PM *To:* WISPA General List *Subject:* Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. /Decision. /We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the /Second Report and Order/, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission’s stated approach in the /Second Report and Order /of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners’ concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point such as a hill or mountain.130 In such cases, the distance at which a TV bands device signal could propagate would be significantly increased, thus increasing the potential for interference to authorized operations in the TV bands. We therefore conclude that it is necessary to modify our rules to limit the antenna HAAT of a fixed device as well as its antenna height above ground. In considering a limit for antenna HAAT, we need to balance the concerns for long range propagation from high points against the typical variability of ground height that occurs in areas where there are significant local high points – we do not want to preclude fixed devices from a large number of sites in areas where there are rolling hills or a large number of relatively high points that do not generally provide open, line-of-sight paths for propagation over long distances. We find that limiting the fixed device antenna HAAT to 106 meters
Re: [WISPA] Transmit Antenna Height
At 9/23/2010 04:50 PM, Brian Webster wrote: If you are on a high mountain and there are also a lot of other high locations around you your HAAT number could still be low. If however you are on a high mountain and the rest of the area all the way around your site is much lower, your HAAT figure will go up. Sites built on side hill locations with the hill rising above in part of the radius will greatly reduce the HAAT number. http://www.fcc.gov/mb/audio/bickel/haat_calculator.htmlhttp://www.fcc.gov/mb/audio/bickel/haat_calculator.html A subscriber's house is wherever it is, and under the new rule, they are just not allowed to subscribe if it is more than 76 meters AAT. This doesn't have to be on top of the high mountain. If you have RadioMobile, you can click around some potential sites and use its US-mode HAAT function. I found a lot of places that would be shut out. Try the hill towns in Berkshire County, MA, or just to its east, so see what I mean. Heck, these are so hilly and woody that the VHF channels look most attractive. (Not that they're available; only one upper-VHF is actually vacant there.) Only a handful of channels meet the white space criteria there to begin with. I have the FCC's contours showing in MapInfo so I can click anywhere on its map and see which contours I'm within. And of course for co-channel, I have to look for contours about 10 miles beyond. If a significant number of subscribers are shut out, not to mention the necessary access points to reach them, then we're stuck again on 900 MHz, which is pretty busy. So even with a white space access point to reach the low houses, we'd need the 900 too to reach the high houses. How silly. How is the HAAT determined? A HAAT value is determined by taking 50 evenly spaced elevation points (above mean sea level [AMSL]) along at least 8 evenly spaced radials from the transmitter site (starting at 0 degrees [True North]). The 50 evenly spaced points are sampled in the segment between 3 to 16 km (formerly 2 to 10 miles) along each radial. The elevation points along each radial are averaged, then the radial averages are averaged to provide the final HAAT value. Terrain variations within 3 km (2 miles) of the transmitter site usually do not have a great impact on station coverage. Brian From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Fred Goldstein Sent: Thursday, September 23, 2010 4:36 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners' concerns about the increased potential for interference
Re: [WISPA] Transmit Antenna Height
Especially since the 900 works in the low areas where you can shut out the noise using the terrain. On 09/23/2010 02:34 PM, Fred Goldstein wrote: At 9/23/2010 04:50 PM, Brian Webster wrote: If you are on a high mountain and there are also a lot of other high locations around you your HAAT number could still be low. If however you are on a high mountain and the rest of the area all the way around your site is much lower, your HAAT figure will go up. Sites built on side hill locations with the hill rising above in part of the radius will greatly reduce the HAAT number. http://www.fcc.gov/mb/audio/bickel/haat_calculator.html A subscriber's house is wherever it is, and under the new rule, they are just not allowed to subscribe if it is more than 76 meters AAT. This doesn't have to be on top of the high mountain. If you have RadioMobile, you can click around some potential sites and use its US-mode HAAT function. I found a lot of places that would be shut out. Try the hill towns in Berkshire County, MA, or just to its east, so see what I mean. Heck, these are so hilly and woody that the VHF channels look most attractive. (Not that they're available; only one upper-VHF is actually vacant there.) Only a handful of channels meet the white space criteria there to begin with. I have the FCC's contours showing in MapInfo so I can click anywhere on its map and see which contours I'm within. And of course for co-channel, I have to look for contours about 10 miles beyond. If a significant number of subscribers are shut out, not to mention the necessary access points to reach them, then we're stuck again on 900 MHz, which is pretty busy. So even with a white space access point to reach the low houses, we'd need the 900 too to reach the high houses. How silly. How is the HAAT determined? A HAAT value is determined by taking 50 evenly spaced elevation points (above mean sea level [AMSL]) along at least 8 evenly spaced radials from the transmitter site (starting at 0 degrees [True North]). The 50 evenly spaced points are sampled in the segment between 3 to 16 km (formerly 2 to 10 miles) along each radial. The elevation points along each radial are averaged, then the radial averages are averaged to provide the final HAAT value. Terrain variations within 3 km (2 miles) of the transmitter site usually do not have a great impact on station coverage. Brian *From:* wireless-boun...@wispa.org [ mailto:wireless-boun...@wispa.org] *On Behalf Of *Fred Goldstein *Sent:* Thursday, September 23, 2010 4:36 PM *To:* WISPA General List *Subject:* Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. /Decision. /We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the /Second Report and Order/, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission’s stated approach in the /Second Report and Order /of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling
Re: [WISPA] Transmit Antenna Height
Make sure to comment to the fcc about this. Get involved and ensure your voice is heard. Fred Goldstein fgoldst...@ionary.com wrote: At 9/23/2010 04:50 PM, Brian Webster wrote: If you are on a high mountain and there are also a lot of other high locations around you your HAAT number could still be low. If however you are on a high mountain and the rest of the area all the way around your site is much lower, your HAAT figure will go up. Sites built on side hill locations with the hill rising above in part of the radius will greatly reduce the HAAT number. http://www.fcc.gov/mb/audio/bickel/haat_calculator.htmlhttp://www.fcc.gov/mb/audio/bickel/haat_calculator.html A subscriber's house is wherever it is, and under the new rule, they are just not allowed to subscribe if it is more than 76 meters AAT. This doesn't have to be on top of the high mountain. If you have RadioMobile, you can click around some potential sites and use its US-mode HAAT function. I found a lot of places that would be shut out. Try the hill towns in Berkshire County, MA, or just to its east, so see what I mean. Heck, these are so hilly and woody that the VHF channels look most attractive. (Not that they're available; only one upper-VHF is actually vacant there.) Only a handful of channels meet the white space criteria there to begin with. I have the FCC's contours showing in MapInfo so I can click anywhere on its map and see which contours I'm within. And of course for co-channel, I have to look for contours about 10 miles beyond. If a significant number of subscribers are shut out, not to mention the necessary access points to reach them, then we're stuck again on 900 MHz, which is pretty busy. So even with a white space access point to reach the low houses, we'd need the 900 too to reach the high houses. How silly. How is the HAAT determined? A HAAT value is determined by taking 50 evenly spaced elevation points (above mean sea level [AMSL]) along at least 8 evenly spaced radials from the transmitter site (starting at 0 degrees [True North]). The 50 evenly spaced points are sampled in the segment between 3 to 16 km (formerly 2 to 10 miles) along each radial. The elevation points along each radial are averaged, then the radial averages are averaged to provide the final HAAT value. Terrain variations within 3 km (2 miles) of the transmitter site usually do not have a great impact on station coverage. Brian From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Fred Goldstein Sent: Thursday, September 23, 2010 4:36 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services
Re: [WISPA] Transmit Antenna Height
Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Fred Goldstein To: WISPA General List Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners' concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point such as a hill or mountain.130 In such cases, the distance at which a TV bands device signal could propagate would be significantly increased, thus increasing the potential for interference to authorized operations in the TV bands. We therefore conclude that it is necessary to modify our rules to limit the antenna HAAT of a fixed device as well as its antenna height above ground. In considering a limit for antenna HAAT, we need to balance the concerns for long range propagation from high points against the typical variability of ground height that occurs in areas where there are significant local high points - we do not want to preclude fixed devices from a large number of sites in areas where there are rolling hills or a large number of relatively high points that do not generally provide open, line-of-sight paths for propagation over long distances. We find that limiting the fixed device antenna HAAT to 106 meters (350 feet), as calculated by the TV bands database, provides an appropriate balance of these concerns. We will therefore restrict fixed TV bands devices from operating at locations where the HAAT of the ground is greater than 76 meters; this will allow use of an antenna at a height of up to 30 meters above ground level to provide an antenna HAAT of 106 meters. Accordingly, we are specifying that a fixed TV bands device antenna may not be located at a site where the ground HAAT is greater than 75 meters
Re: [WISPA] Transmit Antenna Height
But what if you are able to use spectrum around 200 or 300 MHz? That certainly goes through trees. Brian From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Tom DeReggi Sent: Thursday, September 23, 2010 7:32 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Fred mailto:fgoldst...@ionary.com Goldstein To: WISPA General List mailto:wireless@wispa.org Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners' concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point such as a hill or mountain.130 In such cases, the distance at which a TV bands device signal could propagate would be significantly increased, thus increasing the potential for interference to authorized operations in the TV bands. We therefore conclude that it is necessary to modify our rules to limit the antenna HAAT of a fixed device as well as its antenna height above ground. In considering a limit for antenna HAAT, we need to balance the concerns for long range propagation from high points against the typical variability of ground height that occurs in areas where there are significant local high points - we do not want to preclude fixed devices from a large number of sites in areas where there are rolling hills or a large number of relatively high points that do not generally provide open, line-of-sight paths for propagation over long distances. We find that limiting the fixed device antenna HAAT to 106 meters (350 feet), as calculated by the TV bands database, provides an appropriate balance of these concerns. We will therefore restrict fixed TV bands devices from operating at locations
Re: [WISPA] Transmit Antenna Height
At 9/23/2010 07:41 PM, Brian wrote: Content-Type: multipart/alternative; boundary==_NextPart_000_16AA_01CB5B57.64FF81E0 Content-Language: en-us But what if you are able to use spectrum around 200 or 300 MHz? That certainly goes through trees. The rules allow antenna heights up to 30 meters, around 100 feet. One problem with the maximum HAAT limit is that it applies to the ground height, based on having a 30 meter high antenna. In other words, the ruling assumed a maximum antenna HAAT, and then set the ground HAAT to be 30m below that. If somebody's house is 10m below the limit, then a 10m antenna should be legal. (The minimum antenna height went away, since sensing is no longer required. That frankly seems to be the only major improvement in the rules.) Brian From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Tom DeReggi Sent: Thursday, September 23, 2010 7:32 PM To: WISPA General List Subject: Re: [WISPA] Transmit Antenna Height Yeah, that really sucks. Many areas needing served have thick forest/trees easilly 70ft tall. A 90ft height, just wouldn't allow enough of the signal to have open air, and the signal would be going through trees most of the full path. In 900Mhz, the difference between having the tower side over the tree line and below the tree line can be the difference between a quarter mile coverage and a 7 mile coverage in our market. All be it, 700Mhz does have better NLOS propogation characteristics than 900 does. I would have liked to see that height doubled. However, admittedly, it will allow much better spectrum re-use in areas that have a limited number of channels available. Spectrum reuse is one of the best ways to serve more people. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: mailto:fgoldst...@ionary.comFred Goldstein To: mailto:wireless@wispa.orgWISPA General List Sent: Thursday, September 23, 2010 4:36 PM Subject: Re: [WISPA] Transmit Antenna Height This item alone may be the show-stopper, the poison pill that makes it useless to WISPs in much of the country. In places where the routine variation in elevation is more than 75 meters, there will be houses (subscribers) that are more than 76 meters AAT. I notice this in the areas I'm studying, both in the east and in the upper midwest. In a place like Kansas, nobody is 75m AAT. But in the woody Berkshires of Western Massachusetts, the UHF space is needed to get through the trees, and a significant share of houses are 75m AAT. Also, if you want to cover a decent radius, the access point needs to be up the hill too. 75 meters isn't a mountaintop; it's just a little rise. It makes no sense to absolutely ban fixed use at a site that is 100m AAT if the nearest protected-service contour is, say, 50 miles away. A more sensible rule would be to follow broadcast practice, and lower the ERP based on height, so that the distance to a given signal strength contour is held constant as the height rises. Hence a Class A FM station is allowed up to 15 miles, and if it is more than 300 feet AAT, then it is allowed less than the 3000 watts ERP that apply at lower heights. Maybe the lawyers want to have more petitions to argue over. At 9/23/2010 04:07 PM, Rich Harnish wrote: 65. Decision. We decline to increase the maximum permitted transmit antenna height above ground for fixed TV bands devices. As the Commission stated in the Second Report and Order, the 30 meters above ground limit was established as a balance between the benefits of increasing TV bands device transmission range and the need to minimize the impact on licensed services.129 Consistent with the Commission's stated approach in the Second Report and Order of taking a conservative approach in protecting authorized services, we find the prudent course of action is to maintain the previously adopted height limit. If, in the future, experience with TV bands devices indicates that these devices could operate at higher transmit heights without causing interference, the Commission could revisit the height limit. 66. While we expect that specifying a limit on antenna height above ground rather than above average terrain is satisfactory for controlling interference to authorized services in the majority of cases, we also recognize petitioners' concerns about the increased potential for interference in instances where a fixed TV bands device antenna is located on a local geographic high point such as a hill or mountain.130 In such cases, the distance at which a TV bands device signal could propagate would be significantly increased, thus increasing the potential for interference to authorized operations in the TV bands. We therefore conclude that it is necessary to modify our rules to limit the antenna HAAT of a fixed device as well as its antenna height above ground. In considering a limit
